1. Technical Field
This invention is related to the field of subscription television systems generally and, more particularly, to a method and apparatus for providing addressed messages to subscribers and groups of subscribers of a subscription television system.
2. Description of the Relevant Art
In the field of cable television systems, addressable control of cable television descrambling converter equipment is known from U.S. Pat. No. 4,523,922 which generally describes the TotalControl descrambling converter. This converter receives addressed messages directed to it if its converter address matches the address of the addressed message; otherwise, the message is ignored. The message may relate to providing a new level of service ordered in advance by the subscriber. The new level of service is automatically stored in the converter if the address transmitted with the level of service message and the converter's previously stored address match. The channel utilized is an out-of-band channel not normally employed for television transmission, for example, a channel from the FM radio band. The TotalControl message was not of a personal nature; it was typically service related.
Addressed messaging need not relate only to authorizing a new level of subscription television service. In the early 1980's, cable television systems were involved in field trials of energy management, home shopping, home banking, and other services involving one way and two way communication. Consequently, the need for higher capacity messaging channels has increased while the availability of channel capacity has stayed relatively constant; certainly, the cost of providing two or more out-of-band data receivers to increase channel capacity becomes prohibitive. These messages again, while subscriber related, were commercial and not intended for personal use.
In the late 1980's, Scientific-Atlanta, Inc. moved to increase addressed messaging capacity by utilizing pulse amplitude modulation of the audio carrier or an in-band audio data channel for addressed messaging. Most recently, Scientific-Atlanta, Inc. has further suggested the use of otherwise non-utilized portions of the video signal for addressed messaging (see U.S. patent application Ser. Nos. 07/800,241 and 07/983,766, filed Nov. 29, 1991 and Dec. 1, 1992, respectively and incorporated herein by reference as to essential subject matter).
Even with the increased channel capacity, there remained a need to decrease as much as possible the utilization of the available capacity. One technique for doing so is described by U.S. Pat. No. 4,885,775. According to this patent, a screen full or frame of information for display on an associated television receiver is not sent altogether. Rather, predetermined templates that may be utilized for various types of messages may be transmitted in a first step and stored while, in a second step, the variable data completing the template and forming a message is sent. For example, a template may be provided for the current weather conditions which provides descriptors such as time, current temperature, wind velocity, and barometric reading. The template is then completed in a second data transmission.
According to U.S. Pat. No. 4,866,770, messages may be transmitted to individual subscribers or groups of subscribers using a form of block addressing. A group may be formed, for example, of all subscribers interested in sports programming. In this manner, this group of subscribers may be specially authorized to receive certain scrambled sports programming without having to send out individualized messages to each of the members of the group.
Typically, the cable television headend comprises a subscriber database under control of a billing computer provided by one vendor and customer serving equipment under control of a computer provided by the cable television equipment manufacturer. While the billing computer database may be considerably better equipped for assisting the system operator to determine groups of subscribers having common interests, buying habits, birthdays, zip codes, phone exchanges and such, it is the cable equipment or system control computer which is the interface to the subscriber's television terminal where the message is received. Consequently, there has remained in the art an impasse to the provision of individualized and group messaging primarily because of the way the system has evolved. Moreover, there is some considerable possibility that by overcoming these impediments, increased revenues can result, for example, by providing personalized, holiday greeting card services.
Consequently, there remains a need in the art of subscription television services to permit the system operator to provide individualized messages, want ads, public service announcements and such to individuals or groups of individuals.